To meet the demand for wireless data traffic having increased since deployment of 4th generation (4G) communication systems, efforts have been made to develop an improved 5th generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post long term evolution (LTE) System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid frequency shift keying (FSK) and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
A network of a typical 5G communication system may be configured to simultaneously support a multi-radio access technology (RAT) to achieve a wider network coverage and a higher data transfer rate. An example of the RAT includes global systems mobile (GSM), wideband channel division multiple access (WCDMA), high-speed packet access (HSPA), LTE Release 10 carrier aggregation (including a beyond release technique), Institute of Electrical and Electronics Engineers (IEEE) 802.11b/a/g/n/ac/ad/ax/ay, IEEE 802.16a/e, IEEE 802.20, Code Division Multiple Access 2000 1× (CDMA2000 1×) and cdma2000 Evolution-Data Optimized (cdma200 EV-DO), or the like.
More specifically, the network of the 5G communication system is configured in such a manner that a master evolved Node B (MeNB) having a relatively great coverage overlaps with a secondary eNB (SeNB) having a relatively small coverage. Herein, the MeNB includes an anchor eNB, and the SeNB includes a small eNB, an assisting eNB, or a slave eNB. The MeNB and the SeNB may use the same RAT, or may use a different RAT optimized for each overage and usage. For example, in the 5G communication system, the MeNB may use an LTE which is an RAT of a low band (e.g., less than or equal to 6 GHz) for providing a wide coverage, and the SeNB has a relatively small coverage but may use IEEE 802.11ad which is an RAT of an extremely high frequency band (e.g., 60 GHz) capable of achieving a greater data transfer rate.
In the 5G communication system in which the MeNB (or a master RAT (M-RAT)) and the SeNB (or a secondary RAT (S-RAT)) are used in an overlapping manner as described above, a user equipment (UE) basically maintains a connection with the MeNB. Further, the UE may establish an additional connection with the SeNB according to an instruction of the MeNB. However, if the UE is connected with the SeNB according to the instruction of the MeNB, power consumption of the UE is increased since the UE is connected with the SeNB even in a situation where the UE does not have to be connected with the SeNB.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.